Navigation devices, such as GPS-enabled devices, contain maps that are referenced by routing software to determine a route to a desired destination. Navigation devices may have capabilities including: providing maps, including streets maps, displayed in human readable format via text or in a graphical format; turn-by-turn navigation directions to a human in charge of a vehicle or vessel via text or speech; providing directions directly to an autonomous vehicle, such as a robotic probe. As traffic patterns change the available maps become out of date. Navigation devices, as discussed herein, are used according to the current state of the art, that is, the user selects a destination, the position system computes a recommended route, and the device presents directions for the user to follow. In general, the user follows route directions without deviation.
The current state of the art is that satellite-based communication from GPS satellites to GPS devices is one way. It is known to provide websites where a user reports changes in traffic patterns and new roads. It is known to download updated maps via the internet for use by a navigation device.
Turn-by-turn navigation is a feature of some navigation devices where directions for a selected route are continually presented to the user in the form of spoken and visual instructions. Turn-by-turn systems typically use an electronic voice to inform the user whether to turn left or right, the street name, and how much distance to the turn.
It is known to notify a user when most users have not followed a suggested route. Such a notice provides a user with an opportunity to look for missing connections or incorrect turn restrictions, which may have caused a suggested route to not be the route that most users actually took.